Tissue instability or compromise is a common occurrence in all persons, whether induced by age, repeated use, disease, accident or natural and abnormal formation. Such instability may include, for example, intentional or accidental tears, cuts, stretching, loosening, deterioration of structure, loss of firmness, and the like. Furthermore, such tissue may relate to orthopedics, as in the skeletal system and its associated muscles, joints and ligaments and the like, or non-orthopedic systems, such as smooth muscles, gastrointestinal, cardiac, pulmonary, neural, dermal, ocular and the like.
No matter what type of instability is present or whether the tissue to be repaired is classified as orthopedic or non-orthopedic, similar issues and objectives are encountered by the surgeon, namely, creating a stable and reliable structure and doing so in as easy and reliable manner as possible. For example, a neurosurgeon aims to create a stable and reliable adhesion of two neural tissue structures, while at the same time creating minimal damage. The neurosurgeon desires a technique that is minimally invasive, highly reproducible and reliable, and highly effective in connecting the tissue to itself or other similar or dissimilar tissue. It would be even more beneficial to somehow have the tissue become induced to adhere to itself or the other tissue.
In another similar example, in orthopedics soft tissue surgery, the surgeon desires to repair the damaged or diseased tissue in such a manner such that the tissue binds with itself or other tissue in a firm but minimally damaging manner. In muscle or ligament repair, for example, it is necessary to suture the tissue together to promote strength and unity in the structure while at the same time, allow for natural movement to occur.
More broadly, traditional soft tissue repair is a common procedure that typically involves some form of conventional suturing or stapling. For example, certain joints, such as hips, knees, shoulders and elbows contain tissues that are common sources of problems, whether natural or induced, that require extensive physical therapy or surgery to correct. There are similarities between such examples of tissues that present a uniform set of issues for the health care worker such that a treatment of one type of tissue will be in many ways similar to the treatment of another type of tissue, even though the shape, properties and architecture of each tissue is uniquely different. Of such tissues or tissue structures, a common source of medical problems occurs in the joints. Although the below example will be described with respect to the shoulder joint as an example, similar problems are inherent in other soft tissue areas and one having ordinary skill in the art would be cognizant of such problems and how to apply the principles of the present invention to address the problems in such other tissues or tissue systems.
Joint instability is a complex clinical problem associated with a variety of treatment options that include the use of arthroscopic and open surgical methods. For example, for the shoulder joint, open surgical methods for producing a capsular shift to increase the capsular ligament tension and improving the joint stability have been demonstrated. However, adequate arthroscopic methods that approximate the clinical outcome achieved by open surgical methods for reducing excessive joint laxity have been slow to develop or have begun to show less than optimal long term clinical outcomes (e.g., thermal methods).
The shoulder joint, in particular, has inherent instability because of its large range and motion combined with the relatively shallow joint bony socket (glenoid). Anatomically, the rotator cuff acts as the primary dynamic joint stabilizer, while the inferior glenohumeral ligament acts as the primary static shoulder joint stabilizer. Damage to or laxity of one of these stabilizing structures can result in the presentation of clinically relevant shoulder instability.
The onset of shoulder instability is generally associated with a traumatic injury, an atraumatic motion injury, or chronic overuse of the shoulder. Most typically, the instability of the shoulder stems from disruption and/or looseness (excessive capsule laxity) of the shoulder capsule. The resulting subluxation or dislocation of the joint can be painful and debilitating for the individual. The overall approach of shoulder stabilization surgery is to first repair the disrupted/torn capsule and second to tighten the loose capsule ligaments. Of note there are instances where the capsule is intact (e.g., no tear) and only tightening of the capsule ligaments is required to restore joint stability. The ultimate goals of shoulder stabilization include restoring appropriate capsule tension, limiting of humeral head translation, and excessively decreasing range of motion.
Up to 98% of all shoulder joint dislocations occur in the anterior direction, 95% of which are first time dislocations. Over 70% of these individuals will have recurrent instability (subluxation or dislocation) within two years after the first event, potentially requiring surgical intervention.
Certain conventional devices serve to assist with repair of the shoulder capsule when it is disrupted, such as in the case of Bankart Lesions. It is noted that Bankart Lesions are identified by the characteristic stripping/tearing of the anterior inferior labrum from the glenoid. Treatment of these lesions is typically accomplished through a standard open incision or with existing arthroscopic technology.
Clinically described excessive joint laxity in the joint capsule can range from 1.0 to more than 20.0 mm in ligament elongation, resulting in recurrent glenohumeral subluxation or dislocation. A loose shoulder capsule may be tightened readily when a standard open incision is used, but tightening the shoulder capsule arthroscopically poses significant challenges with existing instruments. For example, the acute angles at which the surgical devices are able to approximate the soft tissue and identify regions where suturing would be desirable are limiting. Furthermore, the ability to pass a suture and tie snug surgical knots that compress the tissue in the desired plane with a reasonable suture time is difficult if not cumbersome. Finally, the ability to dictate the level of tissue tied is limited to the tissue needle bite size and remains difficult for the surgeon to reproducibly specify the level of tissue compression desired.
A recently introduced technology, thermal capsulorrhaphy, initially held significant promise as a means of facilitating and expediting arthroscopic shoulder capsule tightening. The premise of this technique is to manipulate the characteristics of the approximately 90% Type I collagen structure of ligaments by thermal exposure. It has been demonstrated that at temperatures above 65 degrees Celsius, collagen begins to denature (e.g., unwinding of the helical structure), resulting in tissue shrinkage. Collagen shrinkage of up to 50% has been demonstrated using thermal energy. However, this technology has yielded equivocal results and progressive skepticism from shoulder surgeons. Specifically, concerns related to long term clinical outcomes for shoulder instability with altered capsular structure have been noted. There is a strong current sentiment among shoulder surgeons that tightening the shoulder capsule by plication with sutures will prove to be more efficacious and more reproducible than the use of thermal mechanisms to reduce the ligament laxity in the capsule.
Additional concerns of thermal capsulorrhaphy application include potential injury to the axillary nerve, bleeding, pain, and excessive swelling of the capsule. More importantly, the technical methods used during thermal capsulorrhaphy do not allow the surgeon to control the level of plication that is desired or anticipated. Specifically, thermal methods are technique-specific and have a required learning curve associated with obtaining specified clinical plication outcomes. Moreover, once treated, the level or resulting tissue alteration achieved is irreversible. The paucity of data demonstrating the long-term mechanical characteristics and viability of these treated ligaments limits the confident and continued use of this technique.
Conventional methods for arthroscopic plication of the shoulder capsule with sutures typically involve freehand techniques that are technically challenging and often time-consuming. An additional shortcoming common to both thermal capsular shrinkage and existing suturing techniques is that neither method can effectively control the amount of capsular tightening in a calibrated fashion. “Over-tightening” of the anterior capsule can lead to problems such as excessive loss of external rotation, limiting shoulder joint function.
Thus, a need exists in the art for an alternative to the conventional methods of tissue repair. There is a need in the art for novel systems and methods for arthroscopic soft tissue repair and/or plication that is adaptable to any soft tissue or soft tissue system and can overcome the shortcomings of conventional methods and improve the clinical outcome as well as be generally adopted by surgeons.